#define _CRT_SECURE_NO_WARNINGS 1

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution {
public:
    ListNode* partition(ListNode* head, int x) {
        ListNode* mini = new ListNode(-1);
        ListNode* large = new ListNode(1);
        ListNode* cur = head, * mcur = mini, * lcur = large;
        while (cur)
        {
            if (cur->val >= x)
            {
                lcur->next = cur;
                lcur = lcur->next;
            }
            else
            {
                mcur->next = cur;
                mcur = mcur->next;
            }
            cur = cur->next;
        }
        mcur->next = large->next;
        lcur->next = nullptr;
        return mini->next;
    }
};